SURFACE OXIDE CALCULATIONS - IDIPOL ?

[jelenajelic]

For the surface oxide slab calculations I have tried to do them in 3 ways:
1) with oxide layer only on one side of the slab (no mirror structure) with IDIPOL=3;
2) with mirror surface without IDIPOL
3) with mirror surface with IDIPOL=3.
I did not include LDIPOL=T in any of the calculations.
Results for the first two gives the similar results for the adsorption energy of the oxygen. Still I am not sure what approach is the right one.
Thanks

[panda]

What is the difference in 1) and 3)? How far apart are the surface energies? Probably 1) and 2) are the same method, since for surface calculations you only count 1/2 of the slab